Cycloidal propeller control mechanism



Nov. 28, 1950 K. F. J. KIRSTEN CYCLOIDAL PROPELLER CONTROL MECHANISMFiled June 15,

5 Sheets-Sheet l Zhwentdr KURT FTJ. KIRSTEN Nov. 28, 1950 K. F. J.KIRSTEN 2, 3 ,235

CYCLOIDAL PROPELLER CONTROL MECHANISM Nov. 28, 1950 K; F. J. KIRSTEN2,532,235

CYCLOIDAL PROPELLER CONTROL MECHANISM Filed June 16, 1947 5 Sheets-Sheet3 a' v a Kur er F? J. KIRSTEN J n M O3 H Cltkornegs 2, a mm m u m K K.F. .J. KIRSTEN V CYCLOIDAL PROPELLER CONTROL MECHANISM M v k g N Nov.28, 1950 Flled June 15 1947 K. F. J. KIRSTEN- CYCLOIDAL PROPELLERCONTROL MECHANISM Nov. 28, 1950 Filed Juna'le, 1947 '5 Sheets-Sheet 53twent0r STE N KURT Fa. K/R

attorneys l atentecl Nov. 2 8 1950 CYCLGIDAL PROPELLER CONTROL MECHANISMKurt F. J. Kirsten, Seattle, Wash. Application June 16, 1947, Serial No.754,822

10 Claims. 1

The propeller described herein is designed primarily for marine use, andmay be considered in the nature of an improvement upon the propellershown and described in my Patent No. 1,740,820, issued December 24,1929.

The present propeller is generally similar to that shown in my aforesaidpatent in that both include a rotor, the outer surface of which liesgenerally in continuation of the hull contour of a ship. This rotorcarries a plurality of blades spaced symmetrically about its peripheryand projecting outward from the rotor in generally parallelrelationship, preferably diverging outwardly somewhat. The drivemechanism for the propeller not only revolves the rotor, but also turnseach blade about its own axis relative to the rotor in a controlledmanner, so that at any given point in the blade orbit successive bladeswill assume the same angular relationship to the rotor. To simplify thefollowing discussion I shall designate propellers of this general typeas cycloidal propellers, whether intended for marine use or for otherpurposes.

In my present propeller the blades do not turn through a completerevolution relative to the rotor, but merely oscillate about theirindividual axes on the blade orbit circle as the rotor revolves, toswing their leading edges alternately outward and inward relative to therespective tangents to such circle through the several blade axes.Preferably the blades are arranged so that all lines perpendicular tothe chords of the respective propeller blades intersect substantially ata common point, designated the blade per pendiculars intersection. Whenthis intersection coincides with the rotative axis of the rotor, all theblades being disposed tangentially of the blade orbit circle, thepropeller will develop no thrust.

If the angular relationship between the blades and the rotor is nowchanged so that the blade perpendiculars intersection is locatedeccentrically of the rotors rotative axis, but within the blade orbitcircle, the propeller will develop thrust in a direction perpendicularboth to the rotative axis of the rotor and to the line joining the rotoraxis and the blade perpendiculars intersection, such line beingdesignated the propellers axis of symmetry, the direction of such thrustdepending upon the sense in which the rotor revolves. In order to changethe direction of the thrust, control mechanism for turning the bladesabout their individual axes simultaneously, to -shift the bladeperpendiculars intersection circumferentially about the rotors axis, isprovided.

The pitch of the propeller is determined by the distance between therotor axis and the blade perpendiculars intersection. When thesecoincide the pitch is zero, and when the blade perpendicularsintersection lies on the'blade orbit circle the propeller pitch ratio,namely the ratio of the propeller pitch to the diameter of its bladeorbit circle, is 11'. Control mechanism for changing the propellerpitchmust be capable of turning the blades to shift the bladeperpendicular-s intersection toward the rotors axis for decreasing thepitch, and away from such axis for increasing the pitch.

The mechanism of my prior Patent No. l,7iO,820 included controlmechanism which could be operated to change the angular relationshipbetween the rotor and all the individual blades simultaneously, todirect the thrust force produced by the blades in any directionperpendicular to the rotors axis of rotation without altering thedirection of rotor rotation. No expedient for varying the propellerpitch was disclosed, however, the pitch ratio being established at thevalue of 1r. It is an object of my present invention to provide controlmechanism for changing the angular relationship between the rotor andall the individual blades simultaneously, not only to change thedirection of the thrust force, but also to change the pitch of thepropeller.

The desirability of changing both propeller pitch and thrust directionhas been recognized heretofore. Ehrhart Patent No. 1,870,674, issuedAugust 9, 1932, for example, shows mechanism for such dual adjustment.The difficulty with Ehrharts blade control mechanism, however, is thatwhile two control devices were employed, they were arrangedperpendicular to each other so that one control device was capable ofacting only along fore and aft chords of the blade orbit circle, and theother control device only along chords athwartships of such circle.Movement of either control actuator would consequently alter both thepropeller pitch and the thrust direction in most instances. To changeonly the propeller pitch or only the thrust direction it was usuallynecessary to operate both control devices, and their coordination toalter one factor without changing the other presented a difficultproblem.

More specifically, therefore, it is an object of my invention to providemechanism for controlling the angular relationship between a cycloidalpropeller rotor and all the blades simultaneously to shift the bladeperpendiculars intersection radially of the blade circle by actuation ofone control device, for changing the propeller pitch, and alternatively,by actuation of the other control device to effect shiftingof the bladeperpendiculars intersection circumferentially of the rotor withoutaltering the eccentricity of such intersection from the rotor axis, thusto alter only the thrust direction. Both operations may, of course, beeifected simultaneously, if desired, by coordinated actuation of the twocontrol devices. Such mechanism may be designated polar blade controlmechanism. An attempt to provide such polar blade control mechanism hadbeen proposed previously in Schneider Patent No. 1,681,500, issuedAugust 21, 1928, but the mechanism disclosed therein would not operatesatisfactorily to accomplish this purpose.

By the mechanism of my present invention I am able to adjust theangularity of the propeller blades, for changing either the propellerpitch or the thrust direction separately, from a station remote from thepropeller installation, selectively and with great accuracy by anyincrement, whether minute or of substantial degree. Moreover my polarblade control mechanism is automatically self-locking and irreversible,so that while either the thrust direction or the pitch of the propeller,or both, may be altered by a simple manipulation of the operator, nostress to which the propeller, or a propeller blade, may be subjected,nor the drive movement of the propeller, can alter the adjustment ofeither control.

As previously stated, the cycloidal propeller disclosed in my Patent No.1,740,820 was of the constant pitch type, as more fully disclosed in myPatent No. 1,432,700, issued October 17, 1922, the pitch ratio of suchpropeller being 1r. While for greatest efiiciency the pitch ratio of acycloidal propeller should be if, a propeller having a variable pitchratio is advantageous. Because of the continuous satelliteunidirectional blade rotation in a propeller having 11' pitch ratio,each blade edge assumes alternately leading and trailing positionsduring successive revolutions of the propeller, whereas if the pitchratio is less than 11', the same edge of each blade is always theleading edge, the blades merely oscillating about their respective axesduring each revolution. Consequently the blade of a low pitch propeller,such as herein disclosed, may be made of hydrofoil or airfoil contour,whereas in a cycloidal propeller having 71- pitch ratio it is necessarythat the opposite edges of the blades be of similar shape. Because ofthe choice of blade profile possible in my present propeller, itsefiiciency at its highest pitch may approach that of a propeller inwhich the blades have 11' ratio, while in addition the advantages ofpitch adjustment over a wide range are secured.

The following description of the mechanism which I prefer for achievingthe objects mentioned will indicate other advantages inherent in variousfeatures of my propeller.

Figure l is a top plan view of a portion of my propeller with partsbroken away to reveal control mechanism. Figure 2 is a transversesection through the propeller along line 22 of Figure 1. Figure 3 is ahorizontal sectional view through part of the propeller taken on line3-3 of Figure 2, parts being broken away. Figure 4 is a horizontalsectional view through the central portion of the propeller takensubstantially on line i-d of Figure 2 and having parts broken away.

Figure 5 is a top perspective view of one slide assembly forming part ofthe blade control mechanism, and Figure 6 is a top perspective view ofpart of a difierent slide assembly.

Figure 7 is a bottom perspective view of a portion of the polar bladecontrol mechanism, parts being in exploded relationship.

Figure 8 is a vertical sectional view taken sub- 4 stantially on line8-8 of Figure 3, showing a propeller blade mounting.

Figures 9, 10, 11, and 12 are diagrammatic illustrations of thepropeller representing various adjusted positions of the thrustdirection and pitch control devices.

While my propeller may be used on other types of apparatus, such as forthe impeller of a pump, and while the principles on which it operatesmay be applied to aeronautical propellers, I have shown in the drawingsand shall describe the preferred form of my propeller for marinepropulsion. The technique disclosed in my Patent No. 1,740,820,mentioned previously, may be followed in installing my present propellerin a vessel. Thus the rotor assembly may be mounted in a circularaperture in the hull I of a boat.

A mounting ring l0 encircling the propeller aperture is embedded in thehull to receive the propeller supporting base it which may be sccured tosuch ring by bolts E2. The base preferably is a casting having acylindrical wall l3 projecting upwardly from it, spaced inwardly fromthe periphery of the base and serving as a housing for the rotor drivemechanism. This wall is braced by gusset ribs [6 extending radiallyoutward from the wall of the propeller at circumferentially spacedlocations. Within the wall a collar 15 extending axially of the base I!defines a central opening to receive the rotor shaft 2. This collar isbraced by circumferentially spaced gusset ribs 86 extending radiallyoutward from it. A circular cover plate [1. bolted about its peripheryto the upper edge of easing wall it, has an additional housing I8projecting upwardly from its central portion, containing my polar bladecontrol mechanism, incorporating thrust direction and pitch controldevices.

The hollow rotor shaft 2, extending downward through collar l5 of thebase, is suspended by thrust bearing 20 secured within a centralaperture of cover plate IT. The lower end of the inner bearing raceabuts a shoulder 2| on the propeller shaft, against which it is pressedby a securing ring 22 encircling the shaft above it. Side loads on thepropeller, produced by reaction to its thrust, are transmitted to base Hthrough a lower radial bearing 23 encircling the lower end of collar l5projecting downward below the central portion of the base. The upperplate 24 of the rotor, which is stiffened by radial ribs 25 spacedcircumferentially about the plate, is apertured centrally to fit theouter race of bearing 23. The lower end of the hollow rotor shaft 2 isflanged outward beneath the inner periphery of plate 24, and the shaftfiange and such plate are bolted together by bolts 2. The outerperiphery of plate 24 is apertured at spaced intervals to receive themounts for the individual propeller blades, which blade mounts aredescribe more particularly in my companion application Serial No.59,534, filed November 28, 1948, entitled Replaceable Propeller BladeStructure. A cap 26 is bolted over each of these apertures.

The peripheral wall 21 of the rotor is of an axial extent such that themarginal portion 28 of the rotor bottom will be disposed flush with theportion of hull l immediately surrounding the aperture in which thepropeller is installed. Preferably the rotors peripheral wall and themarginal portion of the rotor bottom are formed integrally as a singlecasting. The central portion 29 of the rotor bottom is removable,however, to afford access to the mechanism housed within the rotor. Therotor bottom plate 29 may be secured to the outer ring 28 of the rotorbottom by cap screws 29 accessible through apertures in the upper rotorplate 24 closed by removable plugs 29".

The rotor drive mechanism operable to rotate shaft 2 consists of a shaft3 extending radially of the propeller and journaled in suitable bearings3B and 3| supported on the base radially outward from wall l3. The endof this shaft projecting inside such wall carries a drive pinion 32meshing with a ring gear 33 keyed to rotor shaft 2 between itssupporting bearing 2|] and the upper end of base collar I5. The drivepinion and ring gear are beveled suitably in accordance with theirrespective radii. Rotation of drive shaft 3 therefore revolves the rotorto move the individual blades 4 orbitally.

Each propeller blade 4 has a shank 40, which may be merely a bolt,extending axially through a hollow mounting spindle 4|. This spindleprojects completely through the rotor from top to bottom, being receivedin holes in the upper plate 24, previously mentioned, and in smallerholes in the marginal ring 28 of the rotor bottom aligned with the holesin plate 24. Since it is not desirable to admit water to, the interiorof the rotor,

although each mounting spindle 4| rotates with its blades 4 relative tothe rotor, a suitable upper seal 42 and lower seal 43 are providedbetween the spindle and rotor. Despite the fact that the peripheral wall2'! of the rotor is spaced slightly from the sides of thepropeller-receiving hole in the bottom I of the boat, so that, when thepropeller is not rotating, water may flow upward over the top of therotor into the space between its top plate 24 and the stationary base llof the propeller, and even though spindle 4| projects clear through cap26, such packing prevents water from flowing into the interior of therotor either from the top or from the bottom.

A collar 44 is keyed to each mounting spindle 4| and serves as the driveelement for turning the blade 4 carried by such spindle about its ownaxis. This collar is spaced from the cap 26 of its spindle by a radialball bearing 45 received within the upper end of the collar andencircling the central flange of the cap. The lower portion of thespindle receives a similar radial ball bearing 46 encircling the flangeof the spindlereceiving aperture in the rotor bottom. Bearings 45 and 46abut oppositely facing shoulders in the collar so that they resist bothaxial and tilting movement of blades 4.

In such a marine propeller it is desirable to vary the pitch from zeroto a pitch ratio value approaching 11', depending upon the speed atwhich the boat is traveling. The faster the boat travels the highershould be the propeller pitch for a given rotor 'speed. As previouslymentioned, the blades of a variable pitch cycloidal propeller, duringtheir orbital travel, do not rotate unidirectionally about their ownaxes, but oscillate through a fraction of a revolution. The maximumpractical pitch ratio value of such an oscillating blade, true cycloidalpropeller, if excessive turning acceleration of each blade about its ownaxis is to be avoided, is approximately .81r, in which case the maximumdeparture of each blade from a position tangential to the blade orbitcircle in each direction does not exceed about 50 degrees.

In my cycloidal propeller the pitch and the direction of thrust arecontrolled by altering the then more abruptly backward to tangentialposition, and during the half of its revolution through the rearwardsemicircle the leading edge of the blade will first swing abruptlyinward from its tangential position and then more gradually outward totangential position again at the completion of the revolution.Throughout such rotation the blades of a true cycloidal. propeller turnabout their own axes so that the blade perpendiculars of all the bladesat all times will pass through a single intersection point 0. This typeof operation is illustrated by the diagram of Figure 10, the directionin which the vessel travels being indicated by the course arrow C andthe direction of propeller rotation by the arrow R.

The farther the blade perpendiculars intersection is displaced from therotor axis at the center of the blade orbit circle the greater will bethe propeller pitch. Figure 11 shows such intersection at its positionof maximum practical eccentricity, at 0.8 of the radius of the bladeorbit circle from the rotor axis, corresponding to 0.811- pitch ratio ofthe propeller. The location of the blade perpendiculars intersection.angularly about the rotors axis will determine the direction in whichthe propeller thrust acts, the line of thrust always being perpendicularto the propellers axis of symmetry passing through the bladeperpendiculars intersection and the rotor axis, Figures 10 and 11effecting directly forward movement of the vessel in the direction ofthe course arrow C. In Figure 12 the axis of symmetry of the propelleris shown displaced in a clockwise direction through 30 degrees, thepitch adjustment being the same as that of Figure 10. The resultantthrust, correspondingly swung clockwise through 30 degrees fromalignment with the center line of the vessel, will cause the vessel toturn to port as indicated by the course arrow 0.

The blade perpendiculars intersection O of a true cycloidal propeller isrelated to the location of the pin 5, which constitutes the axle for aplurality of bearings 58, one corresponding to each blade. In theinstallation illustrated six blades are provided, so that there must besix bearings 50, and six interconnecting drives, one connecting eachbearing to its respective blade. As part of its interconnecting drive,each bearing carries a block 59 freely rotatable about pin 5 butdisplaced bodily by the pin as it is shifted to change the location ofthe blade perpendiculars intersection. The edges of each block 5!! aredouble beveled, or otherwise shaped complementally to the members of abifurcated slide 5|, having one end supported by such block and itsother end secured rigidly to a gear sector frame 52. Such a slideassembly is shown in Figure 5, and a different form of slide isillustrated in Figure 6, the stacked relationship of the several slideassemblies being shown in Figures 2, 3 and 4. Each gear sector frame isjournaled in bearings 53, the top bearings being received in holes inthe flanged lower end of drive shaft 2, and the lower bearings beingcarried by the bottom rotor plate 29. A hand hole 2%3 in the center ofplate 29 affords access to the interior of the rotor for installingthese bearings when securing such plate in place on the rotor. A directratio exists between the displacement of pin 5 from the center of theorbit circle and the displacement of the blade perpendicularsintersection from such center, being the ratio between the radius of thecircle on which bearings 53 are located and the radius of the bladeorbit circle.

Each gear sector frame 52 carries a gear sector 54 which is swung in itsbearings 53 by the alignment of its slide 5! with pin 5. Eachoscillatory frame gear sector 5 3 meshes with an idler gear 55 which inturn is in mesh with a second gear sector 58 carried by the mountingcollar 54 of the corresponding propeller blade. sectors ti l and 55 areequal. Each idler gear is supported from the upper rotor plate 24 by asuitable bearing. When a slide Ei is swung clockwise to maintain itsalignment with pin 5, its gear sectors 5% and 5t, and consequently therespective blade -l, are also swung clockwise through an equal angle,and vice versa. The interposition of such gearing enables the propellerblade circle diameter to be as great as may be desired, by utilizing atrain of gears for each blade if preferred, while the slide mechanismremains compact so that the stresses on it are low and it can besupported easily, and the adjustability of pin 5 is slight.

Assuming now that pin 5 remains stationary, and is disposed coaxially ofpropeller drive shaft 2, as in Figure 9, the propeller is in zero pitchcondition, and all the slides 5! will extend in directions trulyradially of the propeller blades orbit circle in all rotation positionsof the rotor. No relative reciprocation between pin 5 and slides 5! willtherefore occur, nor will gear segments 54 and 56 and intermediate gears55 rotate relative to each other.

When pin 5 is displaced from a position concentric with shaft 2 towardthe circle of gear sector frame bearings 53, however, as indicated inFigures 10, 11 and 12, the distance between such pin and the axis of aselected pair of bearings 53 will vary as the rotor revolves.Consequently the slide 5! corresponding to such selected pair ofbearings will reciprocate relative to its block fill pivoted on itsbearing 50 as the rotor revolves, while always remaining aligned withpin 5. As a result the slide will shift angularly and this action willresult in the selected gear sector 5 being swung about its bearings 53to oscillate its gear 55 and the blade gear sector 56 meshing with it.The corresponding propeller blade 5 will thus be turned about its ownaxis as it moves orbitally, reflecting the swinging of slide 5! so thatits perpendicular will always pass through a single point O for eachadjusted position of pin 5. Each blade is controlled similarly, so thatall the blade perpendiculars intersect at such point I have providedimproved mechanism for shifting the location of the pin radially to varythe propeller pitch corresponding to different s eeds of the vessel, orcircumferentially to alter the direction of propeller thrust forsteering purposes. Two separate controls can be operated independently,one to change only the direction of thrust and the other only to varythe propeller pitch to any extent desired. Operation of either controlcannot disturb the setting of the other, or both may be movedsimultaneously to change The radii of gear 8 the pitch and the thrustdirection of the propeller conjointly. Mechanism incorporating controldevices capable of such independent operation I designate as the polartype of blade control mechanism.

Pin 5 is carried by a slide 6 supported in suitable ways 60 on amounting plate 6|. This mounting plate is integral with thrust directioncontrol tube 62 which extends concentrically through hollow rotor shaft2. Tube 62 snugly encircles pitch control shaft 63, and such shaft maybe centrally apertured for supply of oil through it to the interior ofthe rotor. Rotation of plate 6! by turning tube 62, when pin 5 is in aposition eccentric of the rotor axis, will shift such pincircumferentially of the rotor axis to vary the direction in which thethrust acts, as indicated in Figure 12.

The innermost shaft 63 carries a pinion 64 at its lower end which isreceived in a groove in slide 8 and meshes with a rack 65 on one side ofsuch groove. Rotation of this shaft to rotate such pinion willreciprocate the slide lengthwise, which is radially of the rotor, tomove pin 5 toward or away from concentricity with main drive shaft 2.Such radial displacement of the pin alters the pitch of the propeller,as explained previously.

Rotor shaft 2 will be rotated continuously to drive the propeller, butit will be evident that tube t2 must not be allowed to rotate: withshaft 2 if the thrust direction is to remain constant, for such rotationwould shift pin '5, controlling the location of the blade perpendicularsintersection, circumferentially around the rotor axis. Consequently theupper end of the thrust direction control tube 62, integral with plate6|, carries a gear 635 fixed to it which meshes with a. worm El normallyconstituting a lock for this shaft so that it will not be rotated byfriction between it and the main propeller shaft 2. By this expedientplate fit is held positivel in a desired rotative position, but it maybe turned at will to alter such position by rotation of worm 57 to turngear 6% through an angle corresponding to: the desired alteration inangle of the thrust direction.

Similarly shaft 63 has a gear 58 keyed to it which, if held stationaryin any rctative position of plate 6i, would prevent alteration in thedegree of eccentricity of pin 5, consequently maintaining the propellerpitch unchanged. A pitch adjusting worm 69 also is provided, operable torotate gear 8 for shifting slide 6 lengthwise, ra-

r dially of the propeller, by rotating gear 84, meshing with rack 65,shown best in Figure 4. It will be noted, however, that worm. as doesnot mesh directly with gear 68, for such direct engagement would notafford the desired control. If such worm and gear did engage directly,gear 64 would be held stationary when shaft 62 is rotated to shift pin 5circumferentially for changing the propeller thrust direction, andconsequently relative movement would occur between such static-nary gear6 and the angularly shifting rack which would effect a radialdisplacement of pin 5, altering the pitch of the propeller as well asthe thrust direction.

To prevent pin 5 llllS being shifted radially tochange the propellerpitch when thrust direction control tube 62' alone is rotated to movesuch circumferentially, differential gearing is interposed between thepitch control worm 5E? and gear secured to the pitch control shaft. Suchdifferential gearing includes a gear I meshing with worm 69 and securedto gear 10. Interposed between and meshing with both gears 68 and ll]are pinions ll carried by a ring 12 which has an, external gear 13encircling its periphery. This external ring gear meshes with a spurgear 14 integral with a second spur gear 75 which meshes with a gear itintegral with the thrust direction gear 66. The sizes of gears 13 and 14are selected with respect to the sizes of gears 15 and 16, so that foreach complete rotation of gear 16 in one direction, gear 13 will berotated one-half a revolution in the same direction. In the arrangementillustrated gears 15 and 16 are of the same diameter, whereas gear Ti isonly one-half the diameter of gear 13.

When pin is in a desired location the thrust direction control tube 62will be held stationary despite rotation of propeller shaft 2 because ofthe direct engagement with worm El of gear 66, keyed to such shaft.Shaft 63 also will be held stationary because gear will hold gears '14and 15 stationary, preventing circumferential shifting of gear 73 andpinions H. As long as worm 69 holds gear 1 stationary, therefore, gear68 also can not rotate to vary the radial location of pin 5 for changingthe propeller pitch. The control mechanism for pin 5 is thus all heldfixed despite rotation of rotor shaft 2.

If it is desired to change the thrust direction, as for steering, whilemaintaining the pitch constant, worm E1 is rotated the desired amount torevolve correspondingly shaft 62. Gear 16 is, of course, rotated throughan equal angle, and ring 12, by the action of gears 73, i4 and 15, isrotated in the same direction but through an angle one-half as great.Assuming that worm 69 is not moved, gear 1 remains stationary to holdgear ii]. AS ring 72 is rotated through a given angle, pinions ii,meshing with stationary gear 70, are both rotated and shifted bodilycircumferentially to turn gear 68, as well as shaft 63 and gear 64,through an angle twice as great as that through which ring 12 moves, andin the same direction. Since ring 12 is turned only half as far as gearit, because of the drive reduction through gears M and 15, the resultantmovement of gear 68, twice that'of the ring 12, corresponds in directionand is equal in degree to the movement of gear 66, which movement ofboth gears 68 and 66 is effected entirely by rotation of worm 61. Plate6|, carried by tube 62, and gear 64, carried by shaft 63 to which gear68 is keyed, are therefore rotated conjointly through equal angles asworm 61 is moved to shift pin 5 circumferentially, so that no relativemovement between gear 64 and rack 65 occurs, avoiding alteration in theeccentricity of pin 5.

If, on the other hand, thrust direction control worm 61 remainsstationary and pitch control worm 69 is rotated, gears 66, 16, l5, l4and 13 can not rotate, and ring '12, carrying pinions 'M will be heldstationary. As gear 1 is rotated by worm 69, therefore, gear 68 will berotated equally, but in the opposite direction, to rotation of gear 1.Such movement of gear 68 will turn shaft 63 and gear 84 to reciprocateslide 6 radially inward or outward without changing the circumferentialposition of pin 5. The propeller pitch change effected by thisoperation, illustrated by Figures 9, 10, and 11, varies the speed of thevessel without altering its course. It is evident, of course, that wormsEl and 69 may be moved simultaneously, if desired, to change both thethrust direction and the propeller pitch conjointly, but in everyinstance the movement of worm 61 will effect the entire change in thrustdirection, while rotation of worm 69 will vary only the propeller pitch.Any friction between propeller shaft 2 and tube 62' produced by rotationof such shaft, and any friction between tube 632 and shaft 63, ispowerless to alter the r'otative positions of such tube or shaft becauseof the positive control and locking mechanism described above which isconnected to them.

When the rotor is not rotating water may flow over the top of it asmentioned previously. To prevent water flowing into the rotor or abovebase I I through the center of the propeller, packing 8 may be providedbetween collar I5 of the base and an annular flange projecting upwardlyfrom the center of the rotor. This packing may be tightened by screwingdownward bolts 8! threaded through webs [6 of the base 1! which pressagainst a packing retainer ring 82. Rotation of the rotor, however, willfree the space between base H and the rotor of water by centrifugalpumping action.

I claim as my invention:

1. A cycloidal propeller or the like, comprising a rotor, a plurality ofblades carried by said rotor, and polar control mechanism for saidblades including a rotative thrust direction control element, a rotativepitch control element disposed concentrically with said thrust directioncontrol element, and blade turning control mechanism operativelyinterconnecting said thrust direction control element, said pitchcontrol element, and said blades, and operable to effect a changedthrust direction turning of said blades by con-,

joint rotation of said thrust direction controlelement and said pitchcontrol element through equal angles and to effect varied pitch turningof said blades by relative rotation of said thrust direction controlelement and said ,pitch control element, and differential gearing meansopera tively interconnecting said thrust direction control element andsaid pitch control element and operable to effect conjoint rotationthereof by rotation of said thrust direction control element forchanging the thrust direction while the propeller pitch remainsunchanged, and further operable, while holding said thrust directioncontrol element against rotation, to eifect rotation of said pitchcontrol element relative to said thrust direction control element byrotation of said pitch control element for altering the propeller pitchwhile the thrust direction remains unchanged. i

2. A cycloidal propeller or the like comprising a rotor, a plurality ofblades carried by said rotor, and polar contol mechanism for said bladesincluding a rotative thrust direction control shaft,

a rotative pitch central shaft disposed concentricallywithin-said thrustdirection control shaft, and blade turning control mechanism operativelyinterconnecting said thrust direction control shaft, said pitch controlshaft, and said blades, and operable to eiiect a changed thrustdirection turning of said blades by conjoint rotation of said thrustdirection control shaft and said pitch con trol shaft in the samedirection and through equal angles, and to effect varied pitch turningof said blades by relative rotation of said pitch control shaft and saidthrust direction control shaft, a thrust direction control worm gearsecured to said thrust direction control shaft, a

thrust direction control worm meshing with said thrust direction controlworm gear, normally locking the same against rotation but rotatable toturn it, a pitch control worm gear, a pitch,

control worm meshing with said pitch control worm gear, normally lockingthe same against rotation but rotatable to turn it, differential gearingoperatively connecting said pitch control worm gear and said pitchcontrol shaft, and reduction spur gearing interconnecting theintermediate gears of said differential gearing and said thrustdirection control shaft, said differential gearing and said reductionspur gearing cooperating, When said pitch control worm gear is locked bysaid pitch control worm, to effect conjoint rotation of said pitchcontrol shaft and said thrust direction control shaft in the samedirection and at the same speed when said thrust direction control shaftis turned by rotation of said thrust direction control worm driving saidthrust direction control worm gear, for changing the thrust directionwhile the propeller pitch remains unchanged, and said differentialgearing being further operable to rotate said pitch control shaftrelative to said thrust direction control shaft when said pitch controlworm is rotated to drive said pitch control worm gear, while said thrustdirection control worm gear and said reduction spur gearing are lockedby said thrust direction control worm, for altering the propeller pitchwhile the thrust direction remains unchanged.

3. A cycloidal propeller or the like comprising a rotor, a plurality ofblades carried by said rotor, a blade turning control element, meanssupporting said blade turning control element for shifting independentlycircumferentially of said rotor to change the thrust direction, andradially of said rotor to alter the propeller pitch, a rotatable blademounting for each propeller blade, a gearing quadrant carried by saidblade mounting, means including a swingable element for each bladecontrolled by said blade turning control element, a gear quadrantcarried by each swingable element and gearing interconnecting said. gearquadrant carried by each swingable element and said gear quadrantcarried by the rotatable mounting of its corresponding blade, operable,as said rotor revolves, to effect controlled turning of said blades inresponse to swinging of said swingable elements as governed by theradial and circumferential location of said blade turning controlelement, and thrust direction and propeller pitch control means operableto shift said blade turning control element circumferentially andradially as desired to change the thrust direction and the propellerpitch.

4. A cycloidal propeller or the like, comprising a rotor, a plurality ofblades carried by said rotor, and polar control mechanism for saidblades including a thrust direction control tube, a pitch control shaftextending through said thrust direction control tube, a control pin,blade-turning mechanism operatively interconnecting said control pin andsaid blades, and operable, as said rotor revolves, to effect controlledturning of said blades as governed by the location of said control pin,a slide carrying said control pin, a guide member carried by said thrustdirection control tube, having guideways engaging said slide and guidingit for movement radially of said rotor, and rotatable by rotation ofsaid thrust direction control tube to shift said control pincircumferentially of the rotors axis, for changing the thrust direction,means operable by rotation of said pitch control shaft to move saidslide in its guideways to shift said control pin radially of the rotorsaxis, for altering the propeller pitch, a thrust direction controlactuator operable to rotate said thrust direction control tube, a pitchcontrol actuator operable to rotate said pitch control shaft, and meansinterconnecting said thrust direction control actuator, said pitchcontrol actuator, said thrust direction control tube and said pitchcontrol shaft, and operable by movement of said thrust direction controlactuator to rotate said thrust direction control tube, to effectrotation of said. pitch control shaft conjointly therewith in the samedirection and to an equal degree,to maintain said slide stationary onsaid guide member as said guide member is rotated by said thrustdirection control tube, to change the thrust direction while maintainingconstant the propeller pitch, and including lost motion means interengaged between said thrust direction control tube said pitch controlactuator and said pitch control shaft and operable to rotate said pitchcontrol shaft by movement of said pitch control actuator while saidthrust direction control tube remains stationary, for shifting saidslide along said guide member radially of the rotor to alter theropeller pitch while the thrust direction remains unchanged.

5. A cycloidal propellor or the like, comprising a tubular drive shaft,a rotor revolved by said drive shaft, a plurality of blades carried bysaid rotor, and polar control mechanism for said blades including athrust direction control tube extending through said tubular drive shaftand rotatable relative thereto, a pitch control shaft extending throughsaid thrust direction control tube, a control pin, blade-turningmechanism operatively interconnecting said control pin and said blades,and operable, as said rotor revolves, to efiect con trolled turning ofsaid blades as governed by the location of said control pin, a slidecarrying said control pin, a guide member carried by said thrustdirection control tube, having guideways engaging said slide and guidingit for movement radially of said rotor, and rotatable by rotation ofsaid thrust direction control tube to shift said control pincircumferentially of the rotors axis, for changing the thrust direction,a rack carried by said slide, a spur gear meshing with said rack andcarried by said pitch control shaft, rotatable to move said slide in itsguideways to shift said control pin radially of the rotors axis, foraltering the propeller pitch, a thrust direction control actuatoroperable to rotate said thrust direction control tube, a pitch controlactuator operable to rotate said pitch control shaft, and meansinterconnecting said thrust direction control actuator, said pitchcontrol actuator, said thrust direction control tube and said pitchcontrol shaft, and operable by movement of said thrust direction controlactuator to rotate said thrust direction control tube, to effectrotation of said pitch control shaft conjointly therewith in the samedirection and to an equal degree, to maintain said slide stationary onsaid guide member as said guide member is rotated by said thrustdirection control tube, to change the thrust direction while maintainingconstant the propeller pitch, and including lost motion meansinterengaged between said thrust direction control tube said pitchcontrol actuator and said pitch control shaft and operable to rotatesaid pitch control shaft by movement of said pitch control actuatorwhile said thrust direction control tube remains stationary, forshifting said slide along said guide member radially of the rotor toalter the propeller pitch while the thrust direction remains unchanged.

6. A cycloidal propeller or the like, comprising a tubular drive shaft,a rotor revolved by said drive shaft, a plurality of blade carried bysaid rotor, and polar control mechanism for said blades including athrust direction control tube extending through said tubular drive shaftand rotatable relative thereto, a pitch control shaft extending throughsaid thrust direction control tube, a control pin, blade-turningmechanism operatively interconnecting said control pin and said blades,and operable, as said rotor revolves, to effect controlled turning ofsaid blades as governed by the location of said control pin, a slidecarrying said control pin, a guide member carried by said thrustdirection control tube, having guideways engaging said slide and guidingit for movement radially of said rotor, and rotatable by rotation ofsaid thrust direction control tube to shift said control pincircumferentially of the rotors axis, for changing the thrust direction,a rack carried by said slide, a spur gear meshing with said rack andcarried by said pitch control shaft, rotatable to move said slide in itsguideways to shift said control pin radially of the rotors axis, foraltering the propeller pitch, and means interconnecting said thrustdirection control tube and said pitch control shaft, including adifferential gear train and a spur gear train arranged in series andoperable to eifect rotation of said pitch control shaft by rotation ofsaid thrust direction control tube and conjointly therewith in the samedirection and to an equal degree to maintain said slide stationary onsaid guide member as said guide member is rotated by said thrustdirection control tube, to change the thrust direction without alteringthe propeller pitch, but inoperative to effect rotation of said thrustdirection control tube by rotation of said pitch control shaft, forshifting said slide along said guide member radially of the rotor toalter the propeller pitch while the thrust direction remains unchanged.

7. A cycloidal propeller or the like, comprising a tubular drive shaft,a rotor revolved by said drive shaft, a plurality of blades carried bysaid rotor, and polar control mechanism for. said blades including athrust direction control tube extending through said tubular drive shaftand rotatable relative thereto, a pitch control shaft extendingconcentrically through said thrust direction control tube, a controlpin, a slide carrying said control pin, a guide member carried by saidthrust direction control tube having guideways engaging said slide andguiding it for movement radially of said rotor, and rotatable byrotation of said thrust direction control tube to shift said control pincircumferentially of the rotors axis for changing the thrust direction,a rack carried by said slide, a spur gear meshing with said rack andcarried by said pitch control shaft, rotatable to move said slide in itsguideways to shift said control pin radially of the rotors axis foraltering the propeller pitch, a rotatable mounting for each propellerblade, means including a swingable element controlled by said controlpin, and gearing interconnecting each swingable element and the mountingof its corresponding blade, operable, as said rotor revolves, to effectcontrolled turning of said blades in response to swinging of saidswingabie elements as governed by the radial and circumferentiallocation of said control pin, a thrust direction control worm gearsecured to said thrust direction control tube, a thrust directioncontrol worm meshing with said thrust direction control worm gear,normally looking the same against rotation but rotatable to turn it, apitch control worm gear, a pitch control worm meshing with said pitchcontrol worm gear, normally locking the same against rotation butrotatable to turn it, differential gearing operatively connecting saidpitch control worm gear and said. pitch control shaft, and reductionspur gearing interconnecting the intermediate gears of said diiferentialgearing and said thrust direction control tube, the differential gearingand said reduction spur gearing cooperating, when said pitch controlworm gear is locked by said pitch control Worm, to effect rotation ofsaid pitch control shaft conjointly with said thrust direction controltube in the Same direction and at the same speed when said thrustdirection control tube is turned by rotation of said thrust directioncontrol worm driving said thrust direction control worm gear, to effectrotation of said guide member without movement of said slide relativethereto for changing the thrust direc-' tion while the propeller pitchremains unchanged, and said differential gearing being furtheroperableto rotate said pitch control shaft relative to said thrust directioncontrol tube, when said pitch control worm is rotated to turn said pitchcontrol worm gear, while said thrust direction control worm gear andsaid reduction spur gearing are locked by said thrust direction controlworm, to effect radial movement of said slide relative to said guidemember by rotation of said first spur gear relative to said rack.without rotation of said guide member, for altering the propeller pitchwhile the thrust direction remains unchanged.

8. A cycloidal propeller or the like comprising a rotor, a plurality ofblades carried by said rotor, and polar control mechanism for saidblades including a thrust direction control element, a pitch controlelement, blade turning control mechanism operatively interconnectingsaid thrust direction control element, said pitch control element, andsaid blades, and operable to effect a changed thrust direction turningof said blades by conjoint movement of said thrust direction controlelement and said pitch control element, and to effect varied pitchturning of said blades by relative movement of said thrust directioncontrol element and said pitch control element, a thrust directioncontrol worm gear secured to said thrust direction control element, athrust direction control worm meshing with said thrust direction controlworm gear, normally locking the same against rotation but rotatable toturn it, a pitch control worm gear, a pitch control worm meshing withsaid pitch control worm gear, normally locking the same against rotationbut operable to turn it, differential gearing operatively connectingsaid pitch control worm gear and said pitch control element, gearingoperatively connecting said differential gearing and said thrustdirection control worm gear and operable, when said pitch control wormgear is locked by said pitch control worm, to effect movement of saiddifferential gearing and in turn of said thrust direction controlelement by rotation of said thrust direction control worm to drive saidthrust direction control Worm gear, for changing the thrust directionwhile the propeller pitch remains unchanged, said differential gearingbeing further operable to effect relative movement of said pitch controlelement and said thrust direction control element when said pitchcontrol worm is rotated to drive said pitch control worm gear, whilesaid thrust direction control worm gear is locked by said thrustdirection control Worm, in turn locking said thrust direction controlelement, for altering the propeller pitch While the thrust directionremains unchanged.

9. A cycloidal propeller or the like comprising a rotary, a plurality ofblades carried by said rotor, and polar control mechanism for saidblades including a blade turning control element, means supporting saidblade turning control element for shifting independentlycircumierentially of said rotor to change the thrust direction, andradially of said rotor to alter the propeller pitch, means operativelyconnecting said blade turning control element to said propeller bladesin all positions of said blade turning control element, and operable, assaid rotor revolves, to efiect controlled turning of said blades inaccordance with the radial and circumferential location of said bladeturning control element, a rotative thrust direction control elementoperatively connected to said blade turning control element, a pitchcontrol element connected With and rotative about the same axis as saidthrust direction control element and operatively connected to said bladeturning control element, said blade turning control element beingshiftable circumferentially of said rotor by conjoint rotation of saidthrust direction control element and said pitch control element abouttheir common axis, and shiftable radially of said rotor by rotationabout such axis of said pitch control element relative to said thrustdirection control element, means operatively connecting said thrustdirection control element and said pitch control element, thrustdirection altering means operatively connected to said connecting meansand operable to move said connecting means for effecting rotation ofsaid pitch control element in synchronism with rotation of said thrustdirection control element about their common axis for shifting saidblade turning control element circumferentially of said rotor Whilemaintaining its same position radially thereof, to change the thrustdirection while preserving constant the propeller pitch, and furtheroperable to hold said thrust direction control element against rotation,and propeller pitch alterin means operatively connected to saidconnecting means and operable to move said connecting means foreffecting rotation of said pitch control element and consequent shiftingof said blade turning control element radially of the rotor without being shifted circumferentially thereof, to alter the propeller pitchwhile said thrust direction altering means holds said thrust directioncontrol element against rotation, thus preserving the thrust directionunchanged.

10. The cycloidal propeller or the like defined in claim 9, in which themeans operatively connecting the blade turning control element to thepropeller blades includes a rotatable blade mounting for each propellerblade, a swingable element controlled by the blade turning controlelement, and gearing interconnecting each swingable element and themounting of its corresponding blade, operable, as said rotor revolves,to effect controlled turning of such blade in response to swinging ofits swingable element as governed by the radial and circumferentiallocation of the blade turning control element.

KURT F. J. KIRSTEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re.19,438 Platt Jan. 22, 1935991,794 McLaughlin May 9, 1911 1,027,217 Schneider May 21, 19121,432,700 Kirsten Oct. 17, 1922 1,681,500 Schneider Aug. 21, 19281,740,820 Kirsten Dec. 24, 1929 1,870,674 Ehrhart Aug. 9, 1932 FOREIGNPATENTS Number Country Date 77,612 Sweden Dec. 7, 1925 490,938 GermanyFeb. 4, 1930

